French Pat. No. 2,339,287 describes a filter for analog signals in which the means for forming the weighted sum are constituted by capacitive dividers whose dividing ratios are determined by the numerical value of the weighting coefficient.
Also known are charge-transfer filters in which the weighting is obtained by means of capacitors with divided plates or with split electrodes.
All these filters are of the transversal type, which in order to obtain satisfactory frequency-selectivity characteristics, require the formation of a sum which comprises many terms.
In these known filters the weighting coefficients can only be positive and smaller than unity.
It is the object of the present invention to provide a filter of the type mentioned in the preamble, which may take the form of any digital-filter configuration (recursive or non-recursive filters).